We believe that YHVH, established a calendar at the Creation. In Genesis we see that He established, Day, Night and the week. Later in Torah He establishes the natural month and instructed His people to observe it.
"Observe the month of Abib (the first month of the year in the Spring), and keep the Passover to the LORD your Elohim (God), for in the month of Abib the LORD your God brought you out of Egypt by night." Deuteronomy 16:1
We practice and encourage others to observe God's set-apart holy days, feasts and festivals.
"And the LORD spoke to Moses, saying, "Speak to the children of Israel, and say to them: 'The feasts of the LORD, which you shall proclaim to be holy convocations, these are My feasts." Leviticus 23:1-2
The Apostles and first century saints also observed these appointed times:
"But concerning the times and the seasons, brethren, you have no need that I should write to you. For you yourselves know perfectly that the day of the LORD so comes as a thief in the night." I Thessalonians 5:1-2
The Apostles did not need to instruct the believers in these things because they were already being practiced.
To determine these days we observe the Biblical Calendar as laid out in Leviticus 23, and throughout Torah. To learn more about the Biblical Calendar that we observe, please check-out our teachings on this subject:
The Biblical Calendar, God's reckoning of Time
The Biblical Calendar 2023 - Part 2